Surface-mounted resistor

Abstract

A highly reliable surface-mounted resistor, which prevents a problem of disconnection between an electrode and a terminal of a chip resistor when heating during mounting, is disclosed. The surface-mounted resistor includes a chip resistor comprising a plate-shaped substrate, a resistance body formed on an upper surface of the substrate, and an electrode connected the resistance body and drawn from the upper surface of the substrate to a lower surface via an end surface, a plate-shaped lead terminal connected to the electrode of the chip resistor, the plate-shaped lead terminal being fixed to the electrode of the substrate on the lower surface side, and an exterior member covering an entire chip resistor and a part of the lead terminal.

What is claimed is: 
     
       1. A surface-mounted resistor comprising:
 a chip resistor comprising a plate-shaped substrate, a resistance body formed on an upper surface of the substrate, and an electrode connected the resistance body and drawn from the upper surface of the substrate to a lower surface of the substrate via an end surface; 
 a plate-shaped lead terminal connected to the electrode, the lead terminal comprising a chip-resistor-connecting portion; and 
 a molded exterior member, 
 wherein the chip-resistor-connecting portion has an L-shape extending along the electrode on the lower surface side and the end surface side of the substrate, and is fixed by an L-shaped solder formed along the electrode on the lower surface side and the end surface side of the substrate, 
 wherein the exterior member covers an entire chip resistor including the electrode on the lower surface side and the end surface side of the substrate, the chip-resistor-connecting portion of the lead terminal, and the solder, and 
 wherein the lead terminal comprises:
 a lead-terminal-connecting portion that extends from the chip-resistor-connecting portion to an outside of the exterior member, and bends downward, and extends along a side surface of the exterior member; and 
 a printed-substrate-connecting portion that extends from the lead-terminal-connecting portion to a lower side of the exterior member, bends downward, and extends along a lower surface of the exterior member. 
 
 
     
     
       2. The surface-mounted resistor according to  claim 1 , wherein the solder does not protrude from a facing surface between the electrode and the lead terminal. 
     
     
       3. A method for manufacturing of a surface-mounted resistor comprising:
 preparing a lead frame and processing the lead frame into a pair of comb shape to form a comb-teeth portion; 
 arranging the lead frame so that tip sides of the comb-teeth portion faces inward; 
 bending the comb-teeth portion to form an L-shaped chip-resistor-connecting portion along an electrode on a lower surface side and an end surface side of a substrate for placing a chip resistor; 
 applying a solder material to the chip-resistor-connecting portion, and placing the electrode of the chip resistor on the chip-resistor-connecting portion to solder the electrode on the lower surface side and the end surface side of the substrate and the chip-resistor-connecting portion in an L-shape by heating; 
 covering an entire chip resistor, the chip-resistor-connecting portion of the comb-teeth portion, and the solder with a molded exterior member to protrude a portion of the comb-teeth portion not covered by the exterior member from a side surface of the exterior member; 
 cutting and bending the comb-teeth portion downward along the side surface of the exterior member to form a portion protruding from the lower surface of the exterior member; and 
 bending the portion protruding from the lower surface of the exterior member to form a printed-substrate-connecting portion extending along the lower surface of the exterior member.